1. Field of the Invention
The present invention relates to a pay broadcast management system and a signal process of a digital receiver and more particularly to a conditional access system (CAS) and method for sending messages from a pay broadcast management system at a specified time and powering on a digital receiver at a predetermined time to allow the digital receiver to receive the messages.
2. Description of Related Art
Typically, broadcast and communication service providers employ a CAS to directly charge fees on use of services with respect to users. For example, as a subscriber management system of the service providers, there is a receiver having a built-in CAS.
There are three types of services requiring subscriber management in the broadcast and communication services: i) a pay per channel; ii) a pay per view (PPV); and iii) an additional service. The pay per channel service charges a predetermined receiving fee on a channel subscribed for and allows for subscribers to watch the programs broadcasted over a relevant channel. The PPV service charges a receiving fee per program taking account of receiving time. The additional service charges a fee on other services supplied via a program as well as a receiving fee on the program. The CAS should operate so that the three types of services can be separately managed.
For this, the CAS assigns a unique encryption or address to each receiver, inputs the unique encryption into a decryptor along with a particular encryption contained in a broadcast signal, detects a new encryption in accordance with a specific calculation method, and reconstructs original signals from broadcast signals which have been scrambled to interfere with reception by a spotter in a sending party using the detected encryption. Accordingly, the CAS comprises an apparatus for allowing only permitted receivers to receive signals and programs and a subscriber management system for pay services. Various methods and principles may be presented depending upon transmission modes and services.
A scrambler/descrambler and an encryptor/decryptor making up the receiver of the CAS are individual apparatus and defined by different national standards. As the scrambler/descrambler, for example, DVB scramblers of DES (Data Encryption Standard) and ETSI (European Telecommunication Standard Institute) in U.S.A. and of ARIB (Association of Radio Industries and Businesses) in Japan are present. The encryptor/decryptor is supposed to be selected and administrated under the responsibility of service providers. For example, there are DSS of Direct TV, Nagra of EchoStar, Nagra of Canal+, and NDS of BskyB. This is because an encryption method depends upon the type of service and a resource subscriber management system of each satellite broadcasting company and must not be administrated under the responsibility of a third party. Each satellite broadcasting company should administrator the CAS having its own special encryptor/decryptor.
As well as present satellite broadcast, satellite broadcast standards of the U.S. or Japan service up link using MODEM as well as down link from satellites. The up link is to transmit used information, i.e., pay broadcast from users to management systems such as a resource subscriber management system (RSMS) through network access. Each receiver is supposed to download a receive control message (RCM) which is a command required for transmission of information on the amount used according to different standards, so the receiver should always be ready for receiving commands such as the RCM. In other words, if information on the amount used in a smart card exceeds 90%, the receiver must inform this information on the amount used to the RSMS. The receiver requests network access and gets a permission for the network access by receiving the RCM message through a satellite thus informing the information on the amount used to the RSMS. Therefore, the receiver should always be xe2x80x9cONxe2x80x9d to receive the RCM message transmission of which cannot be predicted.
Since each receiver receives messages for checking information on the amount used by a user from a satellite, parses the messages at the central processing unit (CPU), decodes them with a smart card, and transmits the information on the amount used to the RSMS through MODEM, most parts of the receiver except a part for processing audio/video signals should always operate in a power-on state. The smart card, which is the size of a general credit card and has an IC chip therewithin, receives information related to conditional access (CA) embedded in a bit stream from a broadcasting station via the MODEM, determines that a channel selected by a user or subscriber is permitted to be presented to the user or subscriber, and charges a subscription fee.
The RCM, an entitlement management message (EMM), and the like for managing the information on the amount used are used to check whether or not the receiver is legal and to reset information which has been stored in the smart card, so the transmit and receive of the messages is not performed in a predetermined cycle. In this reason, the receiver should always be powered on.
The RCM and EMM are messages for up-loading of the information on the amount used. When receivers receive a command to regularly report the amounts used with respect to pay broadcast, the receivers may be designed to perform the up-loading at a time after midnight when communication lines are usually not busy or at a predetermined time which is specified by the RSMS.
Accordingly, receivers should always be xe2x80x9cONxe2x80x9d to receive these messages. This causes considerable power consumption because each receiver consumes the power even while a user does not intend to watch programs broadcasted through the receiver.
Additionally, if the user cuts off the power while the information on the amount used in the smart card is being transmitted to the RSMS after the receiver received the RCM and was allowed to access the network, transmission of the information on the amount used ends in failure and the above processes should be repeated. If the transmission of the information on the amount used ends in failure more than three times, the smart card may be locked and cannot be used.
Accordingly, the present invention is directed to a conditional access system (CAS) and method that substantially obviates one or more of the limitations and disadvantages of the related art.
An objective of the present invention is to provide a conditional access system and method for sending an RCM and/or EMM for checking information on the amount used from an RSMS over a satellite channel at a specified time and powering on a receiver at a predetermined time to allow the receiver to receive and decode the RCM and/or EMM and transmit the information on the amount used to the RSMS.
Another objective of the present invention is to provide a conditional access system and method for informing a receiver of a transmission time(s) of an RCM and/or EMM which are/is non-periodically transmitted at a predetermined time(s) via a satellite channel and automatically powering on the receiver at the informed predetermined time(s) which has been stored at the receiver to allow for the receiver to receive and decode the RCM and/or EMM and transmit information on the amount used to an RSMS.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure as illustrated in the written description and claims hereof, as well as the appended drawings.
To achieve these and other advantages, and in accordance with the purpose of the present invention as embodied and broadly described, a CAS includes: an RSMS for predetermining a time when to transmit an RCM and/or EMM for checking information on the amount used, informing each receiver of the time via a satellite channel, and transmitting the RCM and/or EMM to each receiver at the predetermined time; and a receiver for checking its power state when a time of a timer coincides with the time informed by the RSMS, automatically being turned on if the receiver is in a power off state to receive and decode the RCM and/or EMM so as to acquire permission for network access and then transmit the information on the amount used to the RSMS, and automatically being turned off after completion of the transmission to the RSMS.
In another embodiment, the CAS of the present invention includes: an RSMS for previously informing each receiver of a transmission time(s) of an RCM and/or EMM which are/is non-periodically transmitted at a predetermined time(s) via a satellite channel and transmitting the RCM and/or EMM; and a receiver for storing the informed transmission time information, checking its power state when a time of a timer coincides with the time stored therein, being automatically turned on when the receiver is in a power off state to receive and decode the RCM and/or EMM so as to acquire permission for network access and transmit information on the amount used to the RSMS, and being automatically turned off after completing the transmission of the information.
In another aspect, the present invention provides, for use in a conditional access system having a resource subscriber management system and a receiver including a smart card, a conditional access method comprising the steps of: checking whether or not it is a time selected for transmission of an EMM and/or an RCM between said resource subscriber management system and said receiver; powering on said receiver if it is the time selected and receiving and decoding said EMM or RCM; allowing said receiver to receive a request signal of said resource subscriber management system and acquire a permission for network access and then to transmit information on the amount used with respect to the smart card to said resource subscriber management system; and returning said receiver to its original power state after completion of the transmission of the information on the amount used.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.